Terahertz Emission of Ferromagnetic Ni-Fe Thin Films Excited by Ultrafast Laser Pulses  

作　　者：SHEN Jian ZHANG Huai-Wu LI Yuan-Xun 沈健;张怀武;李元勋(State Key Laboratory of Electronic Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054)

机构地区：[1]State Key Laboratory of Electronic Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054

出　　处：《Chinese Physics Letters》2012年第6期265-267,共3页中国物理快报（英文版）

基　　金：Supported by the Fund for Innovative Research Groups of the National Natural Science Foundation of China(61021061);the National Basic Research Program of China under Grant No 2012CB933104;the Youth Fund of the National Natural Science Foundation of China(No 61001025);the Scientific Fund for College(No ZYGX2011X006);the Fund of Guangdong Province for Research and Industrialization(No 2010B090400314);the Opening Fund of State Key Laboratory(KFJJ201102);the Fund of Key Laboratory of Education Ministry.

摘　　要：It is believed that the ultrafast demagnetization process in ferromagnetic film is intrinsically a thermal effect,which is induced by ultrafast laser pulses.We present experimental evidence that such ultrafast demagnetization of the NiFe thin film can radiate electromagnetic waves in the terahertz range.We also demonstrate that the magnitude of the terahertz electromagnetic pulse emitted from ferromagnetic films alter pulsed laser excitation can be tuned by the Gilbert damping factor α,which is conventionally used to describe damping of GHz precession motion of magnetization.Different damping factors are obtained by varying the normal metal film adjacent to the magnetic film via spin pumping.The measured radiated electric field in the far field is found to be proportional to the Gilbert damping factor.

关 键 词：PUMPING film magnetic 

分 类 号：TN2[电子电信—物理电子学]